1. Field of the Invention
This invention relates to an air brush and more particularly to an air brush having an adjusting function in which the discharge of coating material is adapted to be kept constant by restricting the pulling position of an operating lever.
2. Description of the Related Art
Among conventional air brushes, there is an air brush as shown in FIG. 5. This air brush 100 includes an air brush body 101 having a nozzle 102 provided at a tip end thereof for spraying coating material, and a needle 103 inserted into an axial core section of the air brush body 101 so as to slidably advance and retract along the axial core section of the air brush body 101. At a middle part of the air brush body 101, an operating lever 104 is provided. By depressing the operating lever 104, an air valve 105 is opened. When the air valve 105 is opened, compressed air which is supplied from an air supplying port 112 connected to a lower portion of the air brush body 101 is adapted to be introduced into an air passageway 106 in the air brush body 101 and blew off from the air nozzle 102.
Also, in the air brush 100, when the operating lever 104 is depressed as described above, the blowing-off of the compressed air from the nozzle 102 starts and, when the operating lever 104 is pulled rearward of the air brush body 101 from the situation, a needle chuck 107 is retreated through an operating plate 109 which is bent into a substantially S-shape.
By the retreating of the needle chuck 107, a tip end of the needle 103 chucked by the needle chuck 107 is retreated, thereby opening the nozzle 102. Upon the opening of the nozzle 102, liquid coating material which is sucked up from a container 108 with the foregoing blowing-off of the compressed air is blew off in a finely atomized state from the opened nozzle 102. That is, the depressing of the operating lever 104 causes the blowing-off of the compressed air to start and the rearward pulling of the operating lever 104 causes the coating material to be blew off. Also, according to the pulling amount of the operating lever 104, the amount of the coating material discharging from the nozzle is controlled so as to increase or decrease.
The above-mentioned air brush 100 has an adjusting screw 110 threadedly mounted on a rear end of the needle chuck 107 for fastening and releasing a chucking portion of the needle chuck. The above-mentioned adjusting screw 110 serves as means to adjust a chucking position at which the needle 103 is chucked by the needle chuck 107. For example, the adjusting screw 110 is loosened and the needle 103 is slid rearwardly in a predetermined amount and, thereafter, the adjusting screw 110 is again tightened, whereby the nozzle 102 can be always kept opened in a predetermined amount in state where the operating lever 104 remains unpulled.
Therefore, in the state as described above, when the operating lever 104 is depressed (is not pulled rearwardly), it is possible to always blow off a certain amount of coating material.
However, when the blowing-off amount of the coating material is to be kept constant as described above, it is necessary to perform the following operation. That is, after a cap member 111 which is threadedly mounted in the rear end of the air brush body 101 is removed from the air brush body 101 and the needle 103 is adjusted, the cap member 111 is again mounted in the air brush body 101. Thus, the operation is troublesome.
On the other hand, among conventional air brushes, an air brush with an adjusting mechanism has been developed in the background of the above problem (FIG. 4).
In the air brush 200, a hollow cap member 211 is threadedly connected to a rear end portion of an air brush body 201 and an adjusting finger-grip 212 for adjusting coating material is threadedly mounted in a rear end portion of the hollow cap member 211. The adjusting finger-grip 212 comprises a gripping portion 211a projecting outwardly from a rear end opening of the cap member 211, a threaded portion 211b threadedly mounted in the cap member 211 through the rear end opening of the cap member 211, and a pipe-like abutting portion 212c which is formed integrally with an end of the threaded portion 211b and project from the end of the threaded portion 211b towards an adjusting screw 210.
The air brush is constructed such that in situation where the finger-grip 212 is mounted in the cap member 211 as described above, when the adjusting finger-grip 212 is rotated, the abutting portion 212c is advanced or retreated in an axial core direction of the air brush body and, when an operating lever 204 is pulled, a rear end surface of a retreated adjusting screw 210 is abutted against a front end surface of the abutting portion 212c, thereby limiting the retreating amount of a needle 203.
That is, in the air brush 200 constructed as described above, by the rotational operating of the finger-grip 212, the front end of the abutting portion 212c is moved in the axial core direction, and a position at which the adjusting screw is abutted against the abutting portion when the operating lever is pulled, namely, a retreating position of the needle, is determined, whereby discharging of a certain amount of coating material can be always performed. Therefore, the air brush 200 can use the adjusting function by adjusting the rotation of the adjusting screw 210, without the laborious work of removing the cap member when the retreating position of the needle 203 is adjusted.
As described above, the air brush 200 can easily carry out the adjusting operation of the retreating position of the needle 203. However, the construction of the air brush 200 requires the finger-grip 212 which is threadedly mounted in the rear opening of the cap member 211, so that the number of parts is increased and assembling steps are increased, resulting in additional manufacturing cost being incurred, as compared to the air brush 100 including the cap member 111 only.
An object of the present invention is to provide, in connection with such an air brush as stated above, an arbitrarily adjusting function of the retreating position of the needle without incurring the additional manufacturing cost, and to easily carry out discharging of a certain amount of coating material.
To attain the above object, the air brush according to the present invention includes a substantially cylindrical air brush body having a nozzle provided at a tip end thereof. Inserted into an axial core section of the air brush body is a needle for opening and closing the nozzle which is inserted into and held by a needle chuck which is mounted in the air brush body along the axial core section of the air brush body. Therefore, the needle chuck can hold at a predetermined position the needle inserted therein, and release the needle.
The needle chuck is supported, so as to advance and retract in an axial direction, by an operating lever provided at the air brush body. When the operating lever is operated rearwardly and the needle chuck is retreated, a tip end of the needle is retreated from the nozzle and the nozzle is opened, whereby discharging of coating material is carried out.
Projecting rearwardly of the rear section of the air brush body are a chuck adjusting screw for adjusting the needle chuck so as to tighten and loosen the needle chuck and a rear section of the needle.
A cap member is removably and threadedly connected to the rear section of the air brush body. When the cap member is threadedly connected to the rear section of the air brush body as described above, the adjusting screw and the rear section of the needle are housed in the cap member and covered by the cap member.
When the needle chuck is retreated by the operation of the operating lever, the needle and the chuck adjusting screw are integrally retreated. Provided in an interior of the cap member is an abutting portion. When the needle chuck is retreated by the operation of the operating lever as described above, an end of the chuck adjusting screw is abutted against the abutting portion in the cap member, whereby further retreating of the needle chuck is prevented. That is, by rotating the cap member to cause the cap member to be moved in the axial core direction, the retreating position of the needle is fixed.
Therefore, by rotational operating of the cap member to cause the position of the abutting portion to be moved in an axial direction within the predetermined range, a position (retreating limit) at which the chuck adjusting screw mounted to a rear end of the needle chuck is abutted against the abutting portion is adjustingly moved, and the discharge of coating material from the nozzle is adjustably increased and reduced when the operating lever is operated to the retreating limit.
Furthermore, the air brush according to second aspect of the present invention will be discussed with reference to the following detail description of the preferred embodiment of the present invention.